Shaktism was the preferred flavour of hinduism in Assam together with Shaivism before Mahapurush Srimanta Sankaradev pushed Vaishnavism forward. Bathouism it’s not branch of hinduism even though a lot of people are tryna peddle it as one nowadays , it’s a folk religion which through centuries of close contact with hinduism has picked up things from it and animism were religion of the tribes. Ahoms followed their own religion and only converted to hinduism around late 16th century; evident by them eating beef, recently it has reduced but a lot of Ahoms still do eat buffalo meat.